1. Field of the Invention
The present invention relates generally to a ratchet wrench, and more particularly to a ratchet wrench which is simple in construction and which is faster and less costly to manufacture.
2. Description of the Prior Art
FIGS. 1 and 2 show a conventional bi-directional ratchet wrench, which mainly comprises two flat plates 11, 12, a base 13, a ratchet disposed between the plates 11, 12, a trigger block 15, a spring 16 disposed between the trigger block 15 and the base 13, and a steel ball 17. Rivets 18 are used to assemble the structural elements. The distance between the plates 11 and 12 is the same through-out.
With reference to FIG. 3, which shows another prior bi-directional ratchet wrench intended as an improvement on the above-described ratchet wrench. The ratchet wrench in FIG. 3 comprises an upper plate 41 and a lower plate 42. Each of the plates has two ends which bend in opposite directions, forming a first bent portion and a second bent portion. However, like the prior wrench illustrated in FIGS. 1 and 2, it is also necessary to maintain a uniform distance between the two plates 41 and 42. In other words, the distance between the plates 41 and 42 at the handle portion is equivalent to that between the bent portions of the respective plates 41 and 42. By this arrangement, after a base 43 is secured between the upper plate 41 and the lower plate 42 at the handle portion by rivets, the ratchets 44 pivotally provided at either ends of the base 43 may rotate within their corresponding clearances. Therefore, in order to assemble the wrench as shown in FIG. 3, it is necessary to extend a second upper bent portion 41B of the upper plate 41 so that a ratchet 44 may be pivotally provided between the second bent portion 41B and a second lower bent portion 42B of the lower plate 42, and similarly, a first upper bent portion-41A of the upper plate 41 has to be extended so that another ratchet 44 may be pivotally provided between the first upper bent portion 41A of the upper plate 41 and a first lower bent portion 42A of the lower plate 42. In order to join the two plates 41 and 42 smoothly, a length M of the first upper bent portion 41A of the upper plate 41 has to be different from a length N of the first second bent portion 42A of the lower plate 42, while a length 0 of the second upper bent portion 41B of the upper plate 41 has to be different from a length P of the second lower bent portion 42b of the lower plate 42. A ratchet wrench of such a construction requires that the plates 41 and 42 have the same overall length while the length of the bent portions of the upper plate 41 is different from that of the bent portions of the lower plate 42. Manufacture of such prior wrenches is therefore not only costly but also slow.
FIG. 4 shows another kind of ratchet wrench which consists of an upper plate and a lower plate, and a base disposed between the two plates. The base integrally extends to form a protective flange 5 to provide a better outlook. In this prior art, the length of the bent portions of the upper plate must also be configured to be different from that of the bent portions of the lower plate.